1. Technical Field
Embodiments of the present disclosure relate generally to reliability of circuits, and more specifically to budgeting electromigration-related reliability among metal paths in the design of a circuit.
2. Related Art
A circuit generally refers to a configuration of electrically or electromagnetically connected components or devices. Integrated circuits (IC), printed circuit boards (PCB), IC package with connection leads, or any other type of circuitry in which wires (metal paths) carry currents are some examples of circuits.
Metal paths are provided in circuits to serve as conducting paths between nodes (signal generation points, power/ground, etc.) of the circuit. For example, as is well known in the relevant arts, signal conducting paths among various circuit nodes in an integrated circuit (IC), as well as power supply delivery paths, are typically provided as metal paths.
Electromigration (EM) generally refers to the dislocation of atoms or ions in conducting materials, such as metals due to the flow of current through the conductor. EM may adversely affect (degrade) the structure of metal paths and accordingly the ICs/PCBs may need to designed for EM-reliability.
EM-related reliability may generally be termed as the ability of a circuit to operate in conformance with desired specifications for a specified period of time, despite electromigration and/or electromigration-related effects. A desired (overall) EM reliability measure (e.g., such as number of hours of operation before a failure due to EM in an IC, printed circuit board (PCB), or a device/system incorporating the IC or PCB can occur), is often specified for an IC/PCB. Circuits are generally designed taking into account the EM considerations.
One general requirement in design of circuits with EM considerations is, budgeting a desired reliability measure among the metal paths in a circuit. Budgeting implies that the circuit is designed such that a path would not contribute more than the allocated budget. In general, it is desirable that budgeting be performed such that requirements presented by corresponding environments are satisfied.